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Microsoft Access '97 – 2003 | Page Three | Q and A

This page houses a series of Microsoft Access questions and answers largely aimed at the beginner to intermediate user.

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Can you give me some basic ideas for a database?

A company database might include a personnel table, which in turn might include the following fields: Start date; Position; Department; Salary code; Finish date. Data entered into fields collectively makes a record. There are more basic themes on page 1 of 4.

Do I need a Primary Key?

If you are an absolute beginner, then no! However, preferably every table within an Access database would have a primary key because this ensures that unique fields between tables sharing a relationship are not duplicated. The exception would be where there are no adjoining tables within a database.

How might accuracy be assured?

Perhaps establish a policy to ensure users enter data consistently; make use of Wild Cards in Criteria Expression; utilise controls such as Validation Rules and Input Masks when designing your tables.

How much data can I enter into a text field?

The properties of a text field will default to 50 characters. You can increase this to a maximum of 255 charters during the design process, when structuring your table in Design View.

How should data be entered?

Data should be entered from left to right to ensure accuracy, and to encourage good working practices.

What are DataTypes?

Queries allow us to analyse and change data. The main Query type is a Select Query, allowing users to select specific criteria only, i.e. allow a user to filter specific data from a large database, data file.

What is a database based on?

A database is a Management Information System based on tables of data. Each table containing many records. Each record consisting of any number of fields.

What is a Default Value?

A value that is entered automatically, by default. For example enter a value in the Default Value section within Properties during the design process, e.g. a date: Select a date field and enter: Date()

What is a Validation Rule?

A rule that data entered must comply with, otherwise will not be accepted.

What is a Wild Card?

An asterisk with criteria would be used to return any result. For example: 'Like Smyth' would only return the name 'Smyth'. However: 'Like Sm*' would also return 'Smith' and 'Smiley' perhaps.

What is an Input Mask?

A pattern controlling the data entered into a field, e.g. Telephone Number. However, it is important here to set the DataType to Text. A Wizard facility is optional by clicking to the right of the Input Mask text area within Properties during the design process.

What is Criteria Expression?

An Operator (Comparison), Equal to, for example, is the definition of =. Others: < (Less than); > (Greater than). When the Operator is coupled with Criteria, this is referred to as a Criteria Expression. For example: =£100.00

What is the definition of data?

Data is a piece of information, perhaps referred to as a Field Attribute, e.g. the town (Field) within an address (Record).

What is the definition of information?

A number of data items collectively make up information (A record).

What is the pre-requisite to designing a database?

Plan, consider the purpose of the database? Is it simply to store a small amount of information or to manage larger volumes of data? What type of data is to be stored? What data is needed for output, i.e. what information would you need to look up? What queries/specific criteria might be required?

What is Validation Text?

An error message displayed if criteria does not fit the Validation Rule that has been set.

Why has DataType for telephone numbers been set to Text?

This simplifies the process for the beginner because more complex formatting is required for numerical data which isn't strictly essential here. It is feasible to set the DataType to Number and format within Properties to ensure that leading zeros, in a telephone prefix for example, remain fixed when data is subsequently entered (Enter a zero (0) in Decimal places within the Properties section during the design process). Optionally, create an input mask to control the way in which the data is entered.

Why is accuracy and consistency important?

The person who searches for data may not be the person who entered it. What's more, inaccuracy will show up in the subsequent report/printout.

Why might it be important to set Indexed to No?

Indexing allows control over the way data is displayed when opening the table. When the Index is not set, i.e. set to No, data within a field remains in the order it is entered, less where change to table layout (A-Z sort for example) is applied/saved.

It may be necessary to present the data in the order it was entered, particularly when producing printouts for examination purposes. Equally you might require an index to be set to Yes, in a Post Code field for example, to ensure record order is automatically prioritised to this field… i.e. to ensure that the Post Code field is given order priority.